Applicator

ABSTRACT

AN APPLICATOR APPARATUS FOR PLACING A PRDETERMINED AMOUNT OF MATERIAL EVENLY OVER AN UNEVEN SURFACE. THE APPLICATOR ROLL HAS A COVERING OF RESILIENT MATERIAL. THIS MATERIAL HAS AN OUTER BARRIER SURFACE AND AN INITIAL SHORE DUROMETER OF 60 OR LESS ON THE 00 SCALE. PREFERABLY, IT IS BETWEEN 60 AND   14 ON THE 00 SCALE. THE TRANSFER ROLLS ARE OF HARD MATERIAL. THE TRANSFER ROLL AND THE APPLICATOR ROLL BOTH ROTATE IN THE SAME DIRECTION CAUSING A SLIDING CONTACT BETWEEN THE ROLLS.

United States Patent Inventors Charles Blickenderfer, Jr.

Puyallup; Harold E. Erickson, Federal Way; Charles C. Clapp, Tacoma,Wash.

Appl. No. 871,710

Filed Nov. 20, 1969 Patented June 28, 1971 Assignee WeyerhaeuserCompany, Tacoma, Wash.

Continuation 01 application Ser. No. 7 746,694, July 2, 1968, nowabandoned which is a continuation of application Ser. No. 481,305, Aug.20, 1965, now abandoned.

APPLICATOR 12 Claims, 3 Drawing Figs.

US. Cl 29/132 1nt.CI B21b 31/08 Field of Search 29/ 1 30 PrimaryExaminer-Alfred R. Guest Attorneys.lohn M. Crawford and Patrick D.Coogan ABSTRACT: An applicator apparatus for placing a predeterminedamount of material evenly over an uneven surface. The applicator rollhas a covering of resilient material. This material has an outer barriersurface and an initial Shore Durometer of 60 or less on the 00 scale.Preferably, it is between 60 and 15 on the 00 scale. The transfer rollsare of hard material. The transfer roll and the applicator roll bothrotate in the same direction causing a sliding contact between therolls.

APPLICATOR Related Cases This is a continuation of application Ser. No.764,694 filed July 2, 1968, which is a continuation of application Ser.No. 481,305, filed Aug. 20, I965 both abandoned.

This invention relates to an apparatus for applying adhesives and othermaterials to surfaces having varying thicknesses and varying surfacecharacteristics, and specifically relates to an apparatus for applyingadhesives to wood veneer sheets.

In the manufacture of plywood there are several requirements for theapplication of an adhesive to a veneer sheet.

The first requirement is that a metered quantity of adhesive be placedon the veneer sheet. The adhesives normally used are costly and anyexcessive adhesive that is used will result in a higher cost of plywoodproduced from the veneer.

An excess amount of adhesive on the veneers will also result in longerpress times. The veneers are formed into plywood by being formed intounadhered crossed grain laminae and then being placed into a press whichholds the veneers together and heats the veneers to set the adhesive andbond the veneers together. An excessive amount of adhesive will requirea longer period of heating to activate the adhesive and remove moisturefrom the liquid adhesive. This also will result in greater costs in themanufacture of plywood.

Another requirement is to apply the adhesive over the entire surface ofthe veneer. This is difficult because the veneer has a tendency to curl,and also has surface irregularities such as knots which may protrudeabove'its surface. Therefore, it is necessary to have an applicator rollwhich will conform quickly to the varying surface characteristics of theveneer passing beneath it.

Therefore, it is an object of the present invention to provide anapparatus which will place a predetermined amount of material evenlyover the entire surface of the object passing beneath it. It is afurther object of this invention to provide an apparatus that can placematerial on the uneven surfaces and upon objects having varyingthickness. It is a specific object of this invention to provide anadhesive applicator that will place a predetermined amount of adhesiveevenly over the entire surface of a veneer sheet.

These and other objects will become readily apparent upon a reading ofthe following specification in conjunction with the attached drawings.While the apparatus will be discussed in conjunction with a specificapplication to veneer, it is obvious that the apparatus has broaderapplication.

FIG. 1 is a perspective view of the applicator apparatus including theapplicator roll.

FIG. 2 is a side elevational view partially in section showing theapparatus of FIG. 1.

FIG. 3 is a side elevational view partially in section showing theapparatus of FIGS. 1 and 2 modified for use in a conventional adhesiveapplicator in which both the top and bottom faces of core stock areglued simultaneously as it passes between the two applicator rolls.

The apparatus shown in FIGS. 1 and 2 is used to place adhesive on theupper face of veneer V passing on a conveyor beneath the applicator roll10. The distance between the con veyor surface and the lower surface ofthe applicator roll allows the roll to contact the veneer passingbeneath it. Usually, the roll would be adjusted to rest on the conveyorif no material is passing beneath it. The applicator roll has a centralcore 11, preferably of metal, which is covered with a resilient material12.

The resilient material 12 must be capable of conforming quickly to thesurface characteristics of the veneer passing beneath it so that theadhesive on the roll will be applied to substantially all of the veneersheet passing beneath it. The material 12 must also have an outerbarrier surface so that the portion of the applicator roll contactingthe veneer sheet will have only a predetermined amount of adhesivethereon and will impart only a predetermined amount of adhesive to thesurface of the veneer. It has been found that materials having thesecharacteristics have an initial Shore durometer of 60 or less on the 00scale and usually have a closed cell structure. Materials having aninitial Shore durometer of under 60 on the 00 scale are preferredbecause of their better resiliency. The material most suitable for thisapplication is a flexible, expanded modified polyvinyl chloride closedcell material having an initial Shore durometer of between 15 and 30 onthe 00 scale. The material should be at least %thick.

The material 12 is attached to the core 11 with a cover adhesive 13. Thematerials of the cover and the core and the material being applied willdetermine the cover adhesive to be used. The cover adhesive should beone that is compatible with the materials forming the cover 12 and thecore 11' so that the cover can be adhered to the core, and is compatiblewith the adhesive being applied to the veneer so that it will not beremoved or otherwise be rendered nonadhering by the veneer adhesive.

The veneer adhesive is placed on the veneer by the applicator roll 10.The roll, which has a shaft 14 that is rotatably mounted in bearings 15,rotates in the same direction as the veneer passing beneath it and at aperipheral speed that is equal to the lineal speed of this veneer. Thus,the covering 12 contacts and presses down on the veneer to conform tothe surface of the veneer and place the adhesive on this surface.

The veneer adhesive is spread on the applicator roll 10 by a meteringroll 16, one of a pair of metering rolls 16 and 17. Preferably theserolls have a solid metal core which is covered with a hard rubber.However, one or both of the rolls could be entirely of metal. Theserolls have shafts l8 and 19 which are rotatably mounted in theirrespective bearings 20 and 21.

The spreading of the veneer adhesive onthe applicator roll 10 by themetering roll 16 is caused by the two rolls rotating in the samedirection so that they are moving in opposite directions at their pointof contact, resulting in a sliding contact between the rolls. Themetering rolls pick up adhesive as they move downwardly through theadhesive pool 22 or out of the pan 27 and carry a film outwardly frombeneath the nip. It is obvious that the pan 27 may also be used inconjunction with the rolls I7 and 17a.

The predetermined amount of adhesive imparted to the veneer will dependupon the viscosity or flowability of the adhesive, and on the spacingbetween the metering rolls I6 and 17, and the speed of the meteringrolls 16 and 17. The applicator roll 10 must fit tight against themetering roll 16 and tight against the veneer on the conveyor totransfer the exact amount of glue required. The viscosity and thespacing will determine the amount of adhesive that will be transferredand the amount that will be recirculated. There is never a totaltransference of adhesive from the applicator roll to the veneer.

Preferably, the two metering rolls and the applicator roll are driven bythe conveyor motor. Occasionally it is necessary to raise the applicatorrolls 10 from the conveyor and the air pistons 25 are provided for thispurpose. These pistons are also used to provide the necessary downwardpressure of 20 p.s.i. at the glue line for a good glue transfer to theveneer.

In FIG. 3, the applicator apparatus is used in a conventional gluespreader which places adhesive on both sides of crosscore veneer. Inthis apparatus, the applicator rolls 10a and 10b have the sameconstruction as applicator roll 10, and the metering rolls 16a and 17aand 16b and 17b have the same construction as metering rolls 16 and 17.The rolls 10a and 10b are tangential when no veneer is passing through.The apparatus performs in the same manner as that shown in FIG. 1 exceptthat the applicator rolls 10a and l0b now perform the double function ofapplying adhesive to both sides of the veneer V and of moving the veneerthrough the apparatus.

While specific details of preferred embodiments have been set forthabove, it will be apparent that many changes and modifications may bemade therein without departing from the spirit of the invention. Itwill, therefore, be understood that what is described herein is intendedto be illustrative'only, and is not intended to limit the scope of theinvention.

We claim:

1. An applicator roll having an outer barrier surface which is resilientand has a maximum initial Shore Durometer of 60 on the scale.

2. The applicator roll of claim 1 in which said-roll is surfaced with aclosed cell material.

3. The applicator roll of claim 2 in which said material is polyvinylchloride.

4. In a plywood adhesive apparatus, the improvement of an adhesiveapplicator roll having an outer barrier surface which is resilient andhas a maximum initial Shore Durometer of 60 on the 00 scale.

5. The apparatus of claim 4 in which said roll is surfaced with a closedcell material.

6. The apparatus of claim 5 in which said material is a modifiedpolyvinyl chloride.

7. An applicator roll having an outer barrier surface which is resilientand has a maximum initial Shore Durometer in the range of 15 through 60on the 00 scale.

8. The applicator roll of claim 7 in which said roll is surfaced with aclosed cell material.

9. The applicator roll of claim 8 in which said material is polyvinylchloride.

10. In a plywood adhesive apparatus, the improvement of an adhesiveapplicator roll having an outer barrier surface which is resilient andhas a maximum initial Shore Durometer in the range of l5 through 60 onthe 00 scale.

11. The apparatus of claim 10 in which said roll is surfaced with aclosed cell material.

12. The apparatus of claim 11 in which said material is a modifiedpolyvinyl chloride.

